Emotion is valuable. John Lewis's staff know this - never more than when it unveiled its £7 million Christmas advertising extravaganza, Monty's Christmas, the story of a boy who gives a "dream Christmas" to his imaginary penguin friend.
The tears we have cried over John Lewis's emotional campaigns have brought in hundreds of millions of pounds for the department store - its ads pulled in £1.07 billion in extra sales between 2009 and 2011, and helped with a sales boost of 6.9% for Christmas last year.
John-Lewis-Christmas-fever has made such an impact that it has nestled deep into the heart of our the British establishment. Think I'm exaggerating?
Take The Long Wait - the 2011 ad that featured a boy counting down the days to Christmas, with a beautiful cover of The Smiths' Please, Please, Please, Let Me Get What I Want. It became an official subject for sermons from the Church of England, and more than 7,000 schools, teaching over a million pupils, have downloaded the plan for the assembly devoted to the advert.
William and Kate chose the song recorded specifically for John Lewis's Christmas 2010 advert, Ellie Goulding's cover of Your Song by Elton John, for the first dance at their wedding.
So that's God, royalty and the educational establishment, all buying into the touching sales messages from a snowman, some children, a bear and a hare last year - and a penguin too, if the trend continues this year.
Of course, the reason for this is that the adverts are much more than sales messages. Last year's John Lewis offering, The Bear and The Hare, featured only one actual John Lewis product, an old-school twin-bell alarm clock (for which sales jumped 55% the week after the ad launched.)
Neuroscience studies show that it's an emotional response to an advert makes you most willing to make purchases. A case study about the success of John Lewis adverts, written by its own advertising agencies, was even titled Making The Nation Cry and Buy.
You could argue, then, that we should stop crying at John Lewis ads in protest, because the soppy music, the cute critters, the clever promotion and the merchandise are all a cunning plan to claw our money out of our pockets via our teary eye sockets.
But try not to be so cynical.
Yes, John Lewis's aim is for us to think John Lewis is great, and that once we've bought the turkey we will stuff the remaining car boot space with as many Monty the penguin soft toys as we can.
But if you have a little cry the new ad today, it's ok. You're not welling up because you're imagining the plush Monty that you will soon be buying yourself, you're thinking of the people you'd love so much that you'd give them a whole ocean of stuffed penguins. Walking into a John Lewis store is (hopefully) not going to trigger a bout of uncontrollable sobbing: the emotions we feel when ads move us are personal and connected to our own inner values.
But as so many of us have an absence of religion in our lives, so it's not surprising that we can find these value reflected in commercial sources. Especially at Christmas, we're looking for things that stir us, and that reinforce what human nature is really about. Advertising, with its large budgets and evidence that crying means buying, is hell-bent on giving that to us.
You may think it's disheartening, but adverts can be modern parables - the good ones at least. They can be our psalms, our signposts, our fairy tales and our lessons.
I imagine there are many amazing independent film makers making emotional films about little boys and their penguin friends, but without the marketing budget, they sadly don't often reach us.
So it's not a problem if an advert moves us to tears by reminding us about the positive side of human nature - it's just important that something does.